Find the missing term : 1, 0, 3, 2, 5, 6, ?, 12, 9, 20

Answer: Option C

There are two series in the given question.
1st series: 1, 3, 5, 7, 9 ... ( each next term are generated by adding 2)
2nd series: 0, 2, 6, 12, 20 ... ( each next term are generated by adding 2n [where n=1,2,3,4...])